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Re: [hreg] grid tied system

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  • David Power
    One thing to look forward to is time of use rates. Most of the utilities that I work with are looking at offering these in the next couple of years. As the
    Message 1 of 19 , Oct 26, 2006
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      One thing to look forward to is time of use rates. Most of the utilities that I work with are looking at offering these in the next couple of years. As the high rates coincide with peak power production on a PV system you will be offsetting a much higher cost rate and getting a lower base rate.
       
      David
       
      ----- Original Message -----
      Sent: Thursday, October 26, 2006 1:18 PM
      Subject: RE: [hreg] grid tied system

      Kirk,

      The compensation for net production by your installation is probably a moot
      point since, for a number of reasons, you won't have any. Rather, you will
      be offsetting consumption, and for those kWh, you will be receiving retail
      rates.

      Andrew H. McCalla
      NABCEP Certified Solar PV System Installer (TM)

      Meridian Energy Systems
      2300 S. Lamar, Ste. 107
      Austin, TX 78704

      Voice: (512) 448-0055
      Fax: (512) 448-0045
      www.meridiansolar. com

      -----Original Message-----
      From: hreg@yahoogroups. com [mailto:hreg@yahoogroups. com] On Behalf Of Kirk
      Sent: Thursday, October 26, 2006 1:14 PM
      To: hreg@yahoogroups. com
      Subject: [hreg] grid tied system

      Hi,

      I was looking into doing a grid tied solar arrangement in the
      Houston area.
      I have heard that Reliant is only giving you something like 2 cents
      a kw for power sold back. Does anyone know if this is correct?
      I also am tying to figure out if this a rate set by Centerpoint or
      is this price set by the differnt retail providers (Reliant, TXU
      Energy, green mountain energy, etc.)

      Also, I need clarification on how a grid tied system works, I
      thought it basically spun the meter backwards therefore subtracting
      the energy you provide off the meter (and If you provided more than
      you use, it would result in a refund or the equivalent of selling
      power to the energy company). Is this correct?

      I would love to hear the details of anyone who has done a grid tied
      system in the houston area with details on how they worked with the
      local power providers.

      Regards,

      Kirk

      Yahoo! Groups Links

    • Gary Beck
      Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts - Zero Energy Homes - There are low and zero power home designer/builders in
      Message 2 of 19 , Oct 27, 2006
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        Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –

         

        Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).

         

        Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.

         

        So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?     

         

        Gary Beck, P.E.

        Eco-Holdings LLC

        P.O. Box 25248

        Houston, Texas 77265

         

        Tel: 713-530-1950

        Fax: 832-201-5338


        From: hreg@yahoogroups.com [mailto: hreg@yahoogroups.com ] On Behalf Of Kirk
        Sent: Thursday, October 26, 2006 1:44 PM
        To: hreg@yahoogroups.com
        Subject: [hreg] Re: grid tied system

         

        Thats what I thought, I was just concerned the energy provider would
        meter the power differntly, deducting a reduced rate aginst my
        consumption, if that makes any sense. I have no DELUSIONS of
        producing more power than I use. I was just wanting confirmation. ---
        In hreg@yahoogroups. com, "Andrew McCalla" <andrew@...> wrote:

        >
        > Kirk,
        >
        > The compensation for net production by your installation is
        probably a moot
        > point since, for a number of reasons, you won't have any. Rather,
        you will
        > be offsetting consumption, and for those kWh, you will be
        receiving retail
        > rates.
        >
        >
        > Andrew H. McCalla
        > NABCEP Certified Solar PV System Installer (TM)
        >
        > Meridian Energy Systems
        > 2300 S. Lamar, Ste.
        107
        > Austin ,
        w:st="on">TX 78704
        >
        > Voice: (512) 448-0055
        > Fax: (512) 448-0045
        > www.meridiansolar. com
        >
        >
        >
        > -----Original Message-----
        > From: hreg@yahoogroups. com
        [mailto:hreg@yahoogroups. com] On Behalf
        Of Kirk
        > Sent: Thursday, October 26, 2006 1:14 PM
        > To: hreg@yahoogroups. com
        > Subject: [hreg] grid tied system
        >
        > Hi,
        >
        > I was looking into doing a grid tied solar arrangement in the
        > Houston
        area.
        > I have heard that Reliant is only giving you something like 2
        cents
        > a kw for power sold back. Does anyone know if this is correct?
        > I also am tying to figure out if this a rate set by Centerpoint or
        > is this price set by the differnt retail providers (Reliant, TXU
        > Energy, green mountain energy, etc.)
        >
        > Also, I need clarification on how a grid tied system works, I
        > thought it basically spun the meter backwards therefore
        subtracting
        > the energy you provide off the meter (and If you provided more
        than
        > you use, it would result in a refund or the equivalent of selling
        > power to the energy company). Is this correct?
        >
        > I would love to hear the details of anyone who has done a grid
        tied
        > system in the houston
        area with details on how they worked with
        the
        > local power providers.
        >
        > Regards,
        >
        > Kirk
        >
        >
        >
        >
        >
        > Yahoo! Groups Links
        >

      • Garth & Kim Travis
        Greetings, The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use. Why? DC has major line
        Message 3 of 19 , Oct 27, 2006
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          Greetings,

          The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

          You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

          Bright Blessings,
          Kim


          At 07:32 AM 10/27/2006, you wrote:
          Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –
           
          Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
           
          Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
           
          So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas?    
           
          Gary Beck, P.E.
          Eco-Holdings LLC
          P.O. Box 25248
          Houston, Texas 77265
           
          Tel: 713-530-1950
          Fax: 832-201-5338
        • Kevin Conlin
          I m not an electrical engineer, but I don t see any advantage to having a dual wiring scheme. The cost of the additional wiring and DC distribution panel with
          Message 4 of 19 , Oct 27, 2006
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            I’m not an electrical engineer, but I don’t see any advantage to having a dual wiring scheme.  The cost of the additional wiring and DC distribution panel with DC breakers would be expensive, but the efficiency of a DC system is almost identical to a grid tied AC system. When sizing a DC system I figure 80% efficiency, and an AC grid tied system is generally 78 – 80% efficient.  Considering that the selection of DC appliances is poor compared to AC appliances, and other devices such as a computer or laptop would still require a converter and the associated losses to operate on DC, it is tough to justify the extra expense.  Other devices such as LED lights might have an edge, but they consume very little energy either way.

             

            I also think you have to consider that the reason converters generate heat is because they are not really designed to be high efficiency because there is no economic justification to do so, the small amounts of energy they consume is relatively cheap compared to a water heater or AC unit.

             

             

            ________________________

            Kevin Conlin

            Solarcraft, Inc.

            4007 C Greenbriar

            Stafford, TX 77477-4536

            Local (281) 340-1224

            Toll Free (877) 340-1224

            Fax 281 340 1230

            kconlin@...

            www.solarcraft.net

             

            Please make a note of our new contact information above.

             


            From: Gary Beck [mailto:eco@...]
            Sent: Friday, October 27, 2006 7:32 AM
            To: hreg@yahoogroups.com
            Subject: RE: [hreg] Re: grid tied system

             

            Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –

             

            Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).

             

            Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.

             

            So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas?     

             

            Gary Beck, P.E.

            Eco-Holdings LLC

            P.O. Box 25248

            Houston, Texas 77265

             

            Tel: 713-530-1950

            Fax: 832-201-5338


            From: hreg@yahoogroups.com [mailto:hreg@yahoogroups.com] On Behalf Of Kirk
            Sent: Thursday, October 26, 2006 1:44 PM
            To: hreg@yahoogroups.com
            Subject: [hreg] Re: grid tied system

             

            Thats what I thought, I was just concerned the energy provider would
            meter the power differntly, deducting a reduced rate aginst my
            consumption, if that makes any sense. I have no DELUSIONS of
            producing more power than I use. I was just wanting confirmation. ---
            In hreg@yahoogroups. com, "Andrew McCalla" <andrew@...> wrote:

            >
            > Kirk,
            >
            > The compensation for net production by your installation is
            probably a moot
            > point since, for a number of reasons, you won't have any. Rather,
            you will
            > be offsetting consumption, and for those kWh, you will be
            receiving retail
            > rates.
            >
            >
            > Andrew H. McCalla
            > NABCEP Certified Solar PV System Installer (TM)
            >
            > Meridian Energy Systems
            > 2300 S. Lamar, Ste. 107
            > Austin, TX 78704
            >
            > Voice: (512) 448-0055
            > Fax: (512) 448-0045
            > www.meridiansolar. com
            >
            >
            >
            > -----Original Message-----
            > From: hreg@yahoogroups. com
            [mailto:hreg@yahoogroups. com] On Behalf
            Of Kirk
            > Sent: Thursday, October 26, 2006 1:14 PM
            > To: hreg@yahoogroups. com
            > Subject: [hreg] grid tied system
            >
            > Hi,
            >
            > I was looking into doing a grid tied solar arrangement in the
            > Houston area.
            > I have heard that Reliant is only giving you something like 2
            cents
            > a kw for power sold back. Does anyone know if this is correct?
            > I also am tying to figure out if this a rate set by Centerpoint or
            > is this price set by the differnt retail providers (Reliant, TXU
            > Energy, green mountain energy, etc.)
            >
            > Also, I need clarification on how a grid tied system works, I
            > thought it basically spun the meter backwards therefore
            subtracting
            > the energy you provide off the meter (and If you provided more
            than
            > you use, it would result in a refund or the equivalent of selling
            > power to the energy company). Is this correct?
            >
            > I would love to hear the details of anyone who has done a grid
            tied
            > system in the houston area with details on how they worked with
            the
            > local power providers.
            >
            > Regards,
            >
            > Kirk
            >
            >
            >
            >
            >
            > Yahoo! Groups Links
            >

          • John Miggins
            Kirk, the process is fairly simple and we have found Centerpoint energy to be very accomodating. As Andrew mentioned, there really is no check coming to you
            Message 5 of 19 , Oct 29, 2006
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              Kirk, the process is fairly simple and we have found Centerpoint energy to be very accomodating.  As Andrew mentioned, there really is no check coming to  you in the mail,  You will use the power you generate as offsetting power you buy so you are getting full retail price on your energy, not a bad investment.
               
              Lots of install issues to be aware of such as proper grounding, wiring etc..
              do you have good southern exposure? what is the motivation to do grid tie?  how about solar hot water system it offers quicker payback and coupled with grid tie is a good combination to maximize tax credits.
               
               
               
               
              John Miggins
              Harvest Solar & Wind Power
              "renewable solutions to everyday needs"
              www.harvest-energy.com
              Phone/Fax 918-743-2299
              Cell: 918-521-6223
              ----- Original Message -----
              From: Kirk
              Sent: Thursday, October 26, 2006 12:14 PM
              Subject: [hreg] grid tied system

              Hi,

              I was looking into doing a grid tied solar arrangement in the
              Houston area.
              I have heard that Reliant is only giving you something like 2 cents
              a kw for power sold back. Does anyone know if this is correct?
              I also am tying to figure out if this a rate set by Centerpoint or
              is this price set by the differnt retail providers (Reliant, TXU
              Energy, green mountain energy, etc.)

              Also, I need clarification on how a grid tied system works, I
              thought it basically spun the meter backwards therefore subtracting
              the energy you provide off the meter (and If you provided more than
              you use, it would result in a refund or the equivalent of selling
              power to the energy company). Is this correct?

              I would love to hear the details of anyone who has done a grid tied
              system in the houston area with details on how they worked with the
              local power providers.

              Regards,

              Kirk

            • Gary Beck
              The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production. Any idea how DC line loss
              Message 6 of 19 , Oct 29, 2006
              • 0 Attachment

                The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production.  Any idea how DC line loss compares over 10 feet or 50 feet for typical residential gauge copper wire? A few percent? 10%?

                 

                My point is that solar PV is inherently already a ‘local’ or a distributed low voltage DC power system (rather than a remotely produced and transmitted high voltage power system*).  In comparison a DC-AC-DC-AC path provides multiple opportunities for both electrical energy loss and indoor waste heat production.  Anyone know how do the efficiency conversion numbers might compare?

                 

                (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat production is not a direct issue since transformer is outdoors, in garage or attic, etc.)

                (2) 110V AC to V DC (computer power supply, battery charging etc.  (Same electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor waste-heat production)

                (3) Added AC power* to remove this waste-heat from the house – motor driven electrical refrigeration ‘btu removal’ has a pretty low efficiency - 50%

                 

                So even with a ‘does-it-stick-on-the-wall’  guess, when it happens in this way, I think you are looking at somewhere around 50% to 70% energy ‘loss’ for such a DC-AC-DC-AC path Vs maybe 10% for direct DC path.

                 

                Forget about all ‘DC’ appliances since this is not remotely practical. But consider if on a regional ‘sunny state’ scale, what would happen only if 25% of all future residential lighting and 25% of all residential computer operation power were provided by direct solar DC 18-24V power battery sources?

                 

                Gary Beck, P.E.

                Eco-Holdings LLC

                 

                * This arguement does not even consider that an AC high voltage power production distribution system such as a NG fueled merchant power plant with long transmissions lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before counting any transmission losses.


                From: hreg@yahoogroups.com [mailto: hreg@yahoogroups.com ] On Behalf Of Garth & Kim Travis
                Sent: Friday, October 27, 2006 7:52 AM
                To: hreg@yahoogroups.com
                Subject: RE: [hreg] Re: grid tied system

                 

                Greetings,

                The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

                You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

                Bright Blessings,
                Kim


                At 07:32 AM 10/27/2006, you wrote:

                Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –
                 
                Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
                 
                Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
                 
                So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?    
                 
                Gary Beck, P.E.
                Eco-Holdings LLC
                P.O. Box 25248
                Houston , Texas 77265
                 
                Tel: 713-530-1950
                Fax: 832-201-5338

              • Ariel Thomann
                Several years ago I first got tired of heavy and bulky transformers for almost all new stuff I bought. At that time, the highest voltage item was my Samsung
                Message 7 of 19 , Oct 29, 2006
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                  Several years ago I first got tired of heavy and bulky transformers for almost all new
                  stuff I bought. At that time, the highest voltage item was my Samsung 17-in LCD monitor
                  w/ built in TV "tuner" and speakers (it cost me a small fortune at the time). It uses
                  12 volts.

                  I thought then about having distinctively different "central" 12 volt DC outlets, hoping
                  to get little bitty transformers for electronics using less voltage. My hope was that
                  the various manufacturers would look at standardizing the voltage requirement of their
                  various products. I'm still smoking that pipe...

                  It reminds me of the island of Mayorca, where the standard household voltage was (is?)
                  something weird, like 275 volts -- dating back to the turn of the last century, when the
                  Brits built a small electric railroad, and used that voltage. For the population, the
                  only source of electricity was to steal off the third rail, and that "standard" just
                  stuck.

                  Ariel
                  - We are all Human beings here together. We have to help one another, since otherwise
                  there is NO ONE who will help.
                  - All countries need a NO REGRETS strategic energy policy. Think ahead 7 generations.
                  ------------------------------------

                  > Greetings,
                  >
                  > The original electric grid, way back was DC not
                  > AC, but then Tesla came up the the AC current and
                  > that is what we use. Why? DC has major line
                  > losses. I do run some of my stuff directly off
                  > DC, but I am very careful to have my batteries
                  > really close to where I am using it. Not a
                  > concept that is child friendly. When wiring a
                  > home for AC, until you get a run over 40', you
                  > generally don't worry about putting in more
                  > copper to prevent line losses. With DC power,
                  > the line losses can be measured on a 10'
                  > run. So, unless the power supply is extremely
                  > close to where it will be used, the line losses
                  > will more than make up for any power
                  > savings. This is especially true for any centralized power system in the home.
                  >
                  > You have part of the equation very correct, we
                  > need to deal with all the heat that our modern
                  > living generates. A home that is not designed to
                  > get rid of the heat build up will be very
                  > expensive to opperate. Good ventilation is required.
                  >
                  > Bright Blessings,
                  > Kim
                  >
                  >
                  > At 07:32 AM 10/27/2006, you wrote:
                  >>Some morning thoughts on solar, PVs, energy
                  >>efficiency, and off grid concepts –
                  >>
                  >>Zero Energy Homes - There are low and zero power
                  >>home designer/builders in Texas in business now.
                  >>Their concepts are always based on an extreme
                  >>low energy envelope and maximum natural lighting
                  >>(an oxymoron of sorts). Then a large PV and
                  >>solar hot water system is financed in the
                  >>mortgage allowing an effective payout over 30
                  >>years (versus trying to justify the cost in your
                  >>mind which thinks in much shorter time periods).
                  >>
                  >>Wasted heat counts - Every time you convert DC
                  >>to AC, or low voltage to high voltage, or then
                  >>convert (again) high voltage to low voltage,…
                  >>such as for a desktop computer (happen
                  >>internally), a laptop, or any other transformer
                  >>driven device (answering machine, rechargeable
                  >>tool, Xbox, cordless phone, florescent lighting,
                  >>etc…) you waste and loose energy in the form of
                  >>heat, which you then again waste energy again
                  >>through its removal by running your air conditioning.
                  >>
                  >>So my big thought of the morning and question to
                  >>HREG (and to anyone listening from G.E.,
                  >>Siemens, Sony, Panasonic, Samsung) why hasn’t
                  >>someone come up with a home dual wiring scheme
                  >>for purchase 110 Volt-AC and for produced let’s
                  >>say 24 Volt-DC or 19.9 Volt-DC (a number I
                  >>remember from my laptop converter). Or even
                  >>simpler just sell a PV-Battery home install kit
                  >>system to connect only to (a few) of your many
                  >>home computer devices (HP-Compaq and Reliant -
                  >>are you listening too?). How much energy would that alone save in Texas?
                  >>
                  >>Gary Beck, P.E.
                  >>Eco-Holdings LLC
                  >>P.O. Box 25248
                  >>Houston, Texas 77265
                  >>
                  >>Tel: 713-530-1950
                  >>Fax: 832-201-5338
                • John Miggins
                  Gary, this is an area that we have thought much about in an attempt to reach the holy grail of energy effiiciency, I like your reasoning. DC can play a part
                  Message 8 of 19 , Oct 29, 2006
                  • 0 Attachment
                    Gary, this is an area that we have thought much about in an attempt to reach the holy grail of energy effiiciency, I like your reasoning.  DC can play a part in modern homes just as you suggest, it is more efficient when considering the whole picture although I don't have numbers to back me up.
                     
                    Grid tie is I believe 90% efficient when calculating the DC to AC conversion, most inverters are 94% and higher. off grid DC to AC is 50 to 70% efficient so DC direct would be the most efficient, especially when considering Source AC losses.
                     
                    With smaller houses, centralized power plant, you could approach 30 to 40 feet to any outlet, with larger wiring your losses would be minimized but appliance selection and simple things like attic fans- there is not much selection and the pricing is high.
                     
                     We did a small home with 800 square feet and had DC lighting off of a battery based PV system coupled with energy efficient DC compact fluorescent that worked well.  The lighting was free and quality was nice.  We used regular #10 stranded wiring.
                     
                    For alot of the world, a light bulb is progress.
                     
                     
                    John Miggins
                    Harvest Solar & Wind Power
                    "renewable solutions to everyday needs"
                    www.harvest-energy.com
                    Phone/Fax 918-743-2299
                    Cell: 918-521-6223
                    ----- Original Message -----
                    From: Gary Beck
                    Sent: Sunday, October 29, 2006 12:31 PM
                    Subject: RE: [hreg] Re: grid tied system

                    The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production.  Any idea how DC line loss compares over 10 feet or 50 feet for typical residential gauge copper wire? A few percent? 10%?

                    My point is that solar PV is inherently already a ‘local’ or a distributed low voltage DC power system (rather than a remotely produced and transmitted high voltage power system*).  In comparison a DC-AC-DC-AC path provides multiple opportunities for both electrical energy loss and indoor waste heat production.  Anyone know how do the efficiency conversion numbers might compare?

                    (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat production is not a direct issue since transformer is outdoors, in garage or attic, etc.)

                    (2) 110V AC to V DC (computer power supply, battery charging etc.  (Same electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor waste-heat production)

                    (3) Added AC power* to remove this waste-heat from the house – motor driven electrical refrigeration ‘btu removal’ has a pretty low efficiency - 50%

                    So even with a ‘does-it-stick- on-the-wall’  guess, when it happens in this way, I think you are looking at somewhere around 50% to 70% energy ‘loss’ for such a DC-AC-DC-AC path Vs maybe 10% for direct DC path.

                    Forget about all ‘DC’ appliances since this is not remotely practical. But consider if on a regional ‘sunny state’ scale, what would happen only if 25% of all future residential lighting and 25% of all residential computer operation power were provided by direct solar DC 18-24V power battery sources?

                    Gary Beck, P.E.

                    Eco-Holdings LLC

                    * This arguement does not even consider that an AC high voltage power production distribution system such as a NG fueled merchant power plant with long transmissions lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before counting any transmission losses.


                    From: hreg@yahoogroups. com [mailto: hreg@yahoogroups. com ] On Behalf Of Garth & Kim Travis
                    Sent: Friday, October 27, 2006 7:52 AM
                    To: hreg@yahoogroups. com
                    Subject: RE: [hreg] Re: grid tied system

                    Greetings,

                    The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

                    You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

                    Bright Blessings,
                    Kim


                    At 07:32 AM 10/27/2006, you wrote:

                    Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –
                     
                    Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
                     
                    Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
                     
                    So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?    
                     
                    Gary Beck, P.E.
                    Eco-Holdings LLC
                    P.O. Box 25248
                    Houston , Texas 77265
                     
                    Tel: 713-530-1950
                    Fax: 832-201-5338

                  • Ariel Thomann
                    John: I enjoyed touring your web-site, and particularly re-reading the article. What prompted me to go there, and to write now, is your mention of your 800 sq
                    Message 9 of 19 , Oct 29, 2006
                    • 0 Attachment
                      John: I enjoyed touring your web-site, and particularly re-reading the article. What
                      prompted me to go there, and to write now, is your mention of your 800 sq ft house. I'm
                      looking at building something of that size, and of course an efficient floor plan is
                      critical. Might your floor plan be made available? Thanks!

                      Ariel
                      - We are all Human beings here together. We have to help one another, since otherwise
                      there is NO ONE who will help.
                      - All countries need a NO REGRETS strategic energy policy. Think ahead 7 generations.
                      ------------------------------------

                      > Gary, this is an area that we have thought much about in an attempt to reach the holy
                      > grail of energy effiiciency, I like your reasoning. DC can play a part in modern
                      > homes just as you suggest, it is more efficient when considering the whole picture
                      > although I don't have numbers to back me up.
                      >
                      > Grid tie is I believe 90% efficient when calculating the DC to AC conversion, most
                      > inverters are 94% and higher. off grid DC to AC is 50 to 70% efficient so DC direct
                      > would be the most efficient, especially when considering Source AC losses.
                      >
                      > With smaller houses, centralized power plant, you could approach 30 to 40 feet to any
                      > outlet, with larger wiring your losses would be minimized but appliance selection and
                      > simple things like attic fans- there is not much selection and the pricing is high.
                      >
                      > We did a small home with 800 square feet and had DC lighting off of a battery based
                      > PV system coupled with energy efficient DC compact fluorescent that worked well. The
                      > lighting was free and quality was nice. We used regular #10 stranded wiring.
                      >
                      > For alot of the world, a light bulb is progress.
                      >
                      >
                      > John Miggins
                      > Harvest Solar & Wind Power
                      > "renewable solutions to everyday needs"
                      > www.harvest-energy.com
                      > Phone/Fax 918-743-2299
                      > Cell: 918-521-6223
                      >
                      > ----- Original Message -----
                      > From: Gary Beck
                      > To: hreg@yahoogroups.com
                      > Sent: Sunday, October 29, 2006 12:31 PM
                      > Subject: RE: [hreg] Re: grid tied system
                      >
                      >
                      >
                      > The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion
                      > losses and associated waste heat production. Any idea how DC line loss compares
                      > over 10 feet or 50 feet for typical residential gauge copper wire? A few percent?
                      > 10%?
                      >
                      >
                      >
                      > My point is that solar PV is inherently already a 'local' or a distributed low
                      > voltage DC power system (rather than a remotely produced and transmitted high
                      > voltage power system*). In comparison a DC-AC-DC-AC path provides multiple
                      > opportunities for both electrical energy loss and indoor waste heat production.
                      > Anyone know how do the efficiency conversion numbers might compare?
                      >
                      >
                      >
                      > (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat
                      > production is not a direct issue since transformer is outdoors, in garage or attic,
                      > etc.)
                      >
                      > (2) 110V AC to V DC (computer power supply, battery charging etc. (Same
                      > electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor
                      > waste-heat production)
                      >
                      > (3) Added AC power* to remove this waste-heat from the house - motor driven
                      > electrical refrigeration 'btu removal' has a pretty low efficiency - 50%
                      >
                      >
                      >
                      > So even with a 'does-it-stick-on-the-wall' guess, when it happens in this way, I
                      > think you are looking at somewhere around 50% to 70% energy 'loss' for such a
                      > DC-AC-DC-AC path Vs maybe 10% for direct DC path.
                      >
                      >
                      >
                      > Forget about all 'DC' appliances since this is not remotely practical. But consider
                      > if on a regional 'sunny state' scale, what would happen only if 25% of all future
                      > residential lighting and 25% of all residential computer operation power were
                      > provided by direct solar DC 18-24V power battery sources?
                      >
                      >
                      >
                      > Gary Beck, P.E.
                      >
                      > Eco-Holdings LLC
                      >
                      >
                      >
                      > * This arguement does not even consider that an AC high voltage power production
                      > distribution system such as a NG fueled merchant power plant with long transmissions
                      > lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before
                      > counting any transmission losses.
                      >
                      >
                      > ------------------------------------------------------------------------------
                      >
                      > From: hreg@yahoogroups.com [mailto:hreg@yahoogroups.com] On Behalf Of Garth & Kim
                      > Travis Sent: Friday, October 27, 2006 7:52 AM
                      > To: hreg@yahoogroups.com
                      > Subject: RE: [hreg] Re: grid tied system
                      >
                      >
                      >
                      > Greetings,
                      >
                      > The original electric grid, way back was DC not AC, but then Tesla came up the the
                      > AC current and that is what we use. Why? DC has major line losses. I do run some
                      > of my stuff directly off DC, but I am very careful to have my batteries really close
                      > to where I am using it. Not a concept that is child friendly. When wiring a home
                      > for AC, until you get a run over 40', you generally don't worry about putting in
                      > more copper to prevent line losses. With DC power, the line losses can be measured
                      > on a 10' run. So, unless the power supply is extremely close to where it will be
                      > used, the line losses will more than make up for any power savings. This is
                      > especially true for any centralized power system in the home.
                      >
                      > You have part of the equation very correct, we need to deal with all the heat that
                      > our modern living generates. A home that is not designed to get rid of the heat
                      > build up will be very expensive to opperate. Good ventilation is required.
                      >
                      > Bright Blessings,
                      > Kim
                      >
                      >
                      > At 07:32 AM 10/27/2006, you wrote:
                      >
                      > Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts -
                      >
                      > Zero Energy Homes - There are low and zero power home designer/builders in Texas
                      > in business now. Their concepts are always based on an extreme low energy envelope
                      > and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot
                      > water system is financed in the mortgage allowing an effective payout over 30
                      > years (versus trying to justify the cost in your mind which thinks in much shorter
                      > time periods).
                      >
                      > Wasted heat counts - Every time you convert DC to AC, or low voltage to high
                      > voltage, or then convert (again) high voltage to low voltage,. such as for a
                      > desktop computer (happen internally), a laptop, or any other transformer driven
                      > device (answering machine, rechargeable tool, Xbox, cordless phone, florescent
                      > lighting, etc.) you waste and loose energy in the form of heat, which you then
                      > again waste energy again through its removal by running your air conditioning.
                      >
                      > So my big thought of the morning and question to HREG (and to anyone listening
                      > from G.E., Siemens, Sony, Panasonic, Samsung) why hasn't someone come up with a
                      > home dual wiring scheme for purchase 110 Volt-AC and for produced let's say 24
                      > Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even
                      > simpler just sell a PV-Battery home install kit system to connect only to (a few)
                      > of your many home computer devices (HP-Compaq and Reliant - are you listening
                      > too?). How much energy would that alone save in Texas?
                      >
                      > Gary Beck, P.E.
                      > Eco-Holdings LLC
                      > P.O. Box 25248
                      > Houston, Texas 77265
                      >
                      > Tel: 713-530-1950
                      > Fax: 832-201-5338
                      >
                      >
                      >
                    • Jim & Janet
                      Here is a link to a voltage drop calculator. The easy way. http://nooutage.com/vdrop.htm Or if you are a numbers kinda guy, try this.
                      Message 10 of 19 , Oct 29, 2006
                      • 0 Attachment
                        Here is a link to a voltage drop calculator. The easy way.
                        Or if you are a numbers kinda guy, try this.
                        But don't think that line losses only affect DC power. Here is something interesting if you are really concerned with your energy costs.
                        Jim Duncan
                         
                        ----- Original Message -----
                        From: Gary Beck
                        Sent: Sunday, October 29, 2006 12:31 PM
                        Subject: RE: [hreg] Re: grid tied system

                        The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production.  Any idea how DC line loss compares over 10 feet or 50 feet for typical residential gauge copper wire? A few percent? 10%?

                        My point is that solar PV is inherently already a ‘local’ or a distributed low voltage DC power system (rather than a remotely produced and transmitted high voltage power system*).  In comparison a DC-AC-DC-AC path provides multiple opportunities for both electrical energy loss and indoor waste heat production.  Anyone know how do the efficiency conversion numbers might compare?

                        (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat production is not a direct issue since transformer is outdoors, in garage or attic, etc.)

                        (2) 110V AC to V DC (computer power supply, battery charging etc.  (Same electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor waste-heat production)

                        (3) Added AC power* to remove this waste-heat from the house – motor driven electrical refrigeration ‘btu removal’ has a pretty low efficiency - 50%

                        So even with a ‘does-it-stick- on-the-wall’  guess, when it happens in this way, I think you are looking at somewhere around 50% to 70% energy ‘loss’ for such a DC-AC-DC-AC path Vs maybe 10% for direct DC path.

                        Forget about all ‘DC’ appliances since this is not remotely practical. But consider if on a regional ‘sunny state’ scale, what would happen only if 25% of all future residential lighting and 25% of all residential computer operation power were provided by direct solar DC 18-24V power battery sources?

                        Gary Beck, P.E.

                        Eco-Holdings LLC

                        * This arguement does not even consider that an AC high voltage power production distribution system such as a NG fueled merchant power plant with long transmissions lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before counting any transmission losses.


                        From: hreg@yahoogroups. com [mailto: hreg@yahoogroups. com ] On Behalf Of Garth & Kim Travis
                        Sent: Friday, October 27, 2006 7:52 AM
                        To: hreg@yahoogroups. com
                        Subject: RE: [hreg] Re: grid tied system

                        Greetings,

                        The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

                        You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

                        Bright Blessings,
                        Kim


                        At 07:32 AM 10/27/2006, you wrote:

                        Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –
                         
                        Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
                         
                        Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
                         
                        So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?    
                         
                        Gary Beck, P.E.
                        Eco-Holdings LLC
                        P.O. Box 25248
                        Houston , Texas 77265
                         
                        Tel: 713-530-1950
                        Fax: 832-201-5338

                      • Prasad Enjeti
                        Here is another link which details the amount of standby power all our home appliances consume. Click on the link on the left - Home Tours.. a typical US home
                        Message 11 of 19 , Oct 29, 2006
                        • 0 Attachment
                          Here is another link which details the amount of standby power all our home appliances consume. Click on the link on the left - Home Tours.. a typical US home consumes ~ 100 Watts of electricity when everything in the house is turned off..
                           
                          ************************************************************
                          Dr. Prasad Enjeti Power Electronics & Power Quality Laboratory
                          Professor, Fellow of IEEE Department of Electrical Engineering
                          Texas A&M University
                          College Station, TX - 77843-3128
                          Tel: 979-845-7466
                          Fax: 979-845-6259
                          Email: enjeti@... ; http://enjeti.tamu.edu
                          *************************************************************


                          ----- Original Message ----
                          From: Jim & Janet <jhd1@...>
                          To: hreg@yahoogroups.com
                          Sent: Sunday, October 29, 2006 5:05:05 PM
                          Subject: Re: [hreg] Re: grid tied system

                          Here is a link to a voltage drop calculator. The easy way.
                          Or if you are a numbers kinda guy, try this.
                          But don't think that line losses only affect DC power. Here is something interesting if you are really concerned with your energy costs.
                          Jim Duncan
                           
                          ----- Original Message -----
                          From: Gary Beck
                          Sent: Sunday, October 29, 2006 12:31 PM
                          Subject: RE: [hreg] Re: grid tied system

                          The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production.  Any idea how DC line loss compares over 10 feet or 50 feet for typical residential gauge copper wire? A few percent? 10%?

                          My point is that solar PV is inherently already a ‘local’ or a distributed low voltage DC power system (rather than a remotely produced and transmitted high voltage power system*).  In comparison a DC-AC-DC-AC path provides multiple opportunities for both electrical energy loss and indoor waste heat production.  Anyone know how do the efficiency conversion numbers might compare?

                          (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat production is not a direct issue since transformer is outdoors, in garage or attic, etc.)

                          (2) 110V AC to V DC (computer power supply, battery charging etc.  (Same electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor waste-heat production)

                          (3) Added AC power* to remove this waste-heat from the house – motor driven electrical refrigeration ‘btu removal’ has a pretty low efficiency - 50%

                          So even with a ‘does-it-stick- on-the-wall’  guess, when it happens in this way, I think you are looking at somewhere around 50% to 70% energy ‘loss’ for such a DC-AC-DC-AC path Vs maybe 10% for direct DC path.

                          Forget about all ‘DC’ appliances since this is not remotely practical. But consider if on a regional ‘sunny state’ scale, what would happen only if 25% of all future residential lighting and 25% of all residential computer operation power were provided by direct solar DC 18-24V power battery sources?

                          Gary Beck, P.E.

                          Eco-Holdings LLC

                          * This arguement does not even consider that an AC high voltage power production distribution system such as a NG fueled merchant power plant with long transmissions lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before counting any transmission losses.


                          From: hreg@yahoogroups. com [mailto: hreg@yahoogroups. com ] On Behalf Of Garth & Kim Travis
                          Sent: Friday, October 27, 2006 7:52 AM
                          To: hreg@yahoogroups. com
                          Subject: RE: [hreg] Re: grid tied system

                          Greetings,

                          The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

                          You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

                          Bright Blessings,
                          Kim


                          At 07:32 AM 10/27/2006, you wrote:

                          Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –
                           
                          Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
                           
                          Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
                           
                          So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?    
                           
                          Gary Beck, P.E.
                          Eco-Holdings LLC
                          P.O. Box 25248
                          Houston , Texas 77265
                           
                          Tel: 713-530-1950
                          Fax: 832-201-5338



                        • Gary Beck
                          Interesting - 100 watts when everything is off . Times 100,000,000 households is 3000 Megawatts (or did I miss a zero?). If not, this is about 6 merchant
                          Message 12 of 19 , Oct 29, 2006
                          • 0 Attachment

                            Interesting - 100 watts when everything is ‘off’.  Times 100,000,000 households is 3000 Megawatts (or did I miss a zero?). If not, this is about 6 merchant power plants operating 24x7.

                             

                            If each house turned on just 3 – 60 Watt incandecent (hot) light bulbs, this jumps above 10,000 MW. So now 20 merchant plants each likely burning some type of fossil fuel and we have just 3 lights on.

                             

                            Actually, due to transmission and distribution losses, many more plants burning much more fuel. Solar-DC-Battery auxilary wiring for lighting alone sounds even better.

                             


                            From: hreg@yahoogroups.com [mailto: hreg@yahoogroups.com ] On Behalf Of Prasad Enjeti
                            Sent: Sunday, October 29, 2006 5:44 PM
                            To: hreg@yahoogroups.com
                            Subject: Re: [hreg] Re: grid tied system

                             

                            Here is another link which details the amount of standby power all our home appliances consume. Click on the link on the left - Home Tours .. a typical US home consumes ~ 100 Watts of electricity when everything in the house is turned off..

                             

                            ************ ********* ********* ********* ********* ********* ***
                            Dr. Prasad Enjeti Power Electronics & Power Quality Laboratory
                            Professor, Fellow of IEEE Department of Electrical Engineering
                            Texas A&M University
                            College Station , TX - 77843-3128
                            Tel: 979-845-7466
                            Fax: 979-845-6259
                            Email: enjeti@.... edu ; http://enjeti. tamu.edu
                            ************ ********* ********* ********* ********* ********* ****

                             

                            ----- Original Message ----
                            From: Jim & Janet <jhd1@earthlink. net>
                            To: hreg@yahoogroups. com
                            Sent: Sunday, October 29, 2006 5:05:05 PM
                            Subject: Re: [hreg] Re: grid tied system

                            Here is a link to a voltage drop calculator. The easy way.

                            Or if you are a numbers kinda guy, try this.

                            But don't think that line losses only affect DC power. Here is something interesting if you are really concerned with your energy costs.

                            Jim Duncan

                             

                            ----- Original Message -----

                            From: Gary Beck

                            Sent: Sunday, October 29, 2006 12:31 PM

                            Subject: RE: [hreg] Re: grid tied system

                             

                            The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production.  Any idea how DC line loss compares over 10 feet or 50 feet for typical residential gauge copper wire? A few percent? 10%?

                            My point is that solar PV is inherently already a ‘local’ or a distributed low voltage DC power system (rather than a remotely produced and transmitted high voltage power system*).  In comparison a DC-AC-DC-AC path provides multiple opportunities for both electrical energy loss and indoor waste heat production.  Anyone know how do the efficiency conversion numbers might compare?

                            (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat production is not a direct issue since transformer is outdoors, in garage or attic, etc.)

                            (2) 110V AC to V DC (computer power supply, battery charging etc.  (Same electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor waste-heat production)

                            (3) Added AC power* to remove this waste-heat from the house – motor driven electrical refrigeration ‘btu removal’ has a pretty low efficiency - 50%

                            So even with a ‘does-it-stick- on-the-wall’  guess, when it happens in this way, I think you are looking at somewhere around 50% to 70% energy ‘loss’ for such a DC-AC-DC-AC path Vs maybe 10% for direct DC path.

                            Forget about all ‘DC’ appliances since this is not remotely practical. But consider if on a regional ‘sunny state’ scale, what would happen only if 25% of all future residential lighting and 25% of all residential computer operation power were provided by direct solar DC 18-24V power battery sources?

                            Gary Beck, P.E.

                            Eco-Holdings LLC

                            * This arguement does not even consider that an AC high voltage power production distribution system such as a NG fueled merchant power plant with long transmissions lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before counting any transmission losses.


                            From: hreg@yahoogroups. com [mailto: hreg@yahoogroups. com ] On Behalf Of Garth & Kim Travis
                            Sent: Friday, October 27, 2006 7:52 AM
                            To: hreg@yahoogroups. com
                            Subject: RE: [hreg] Re: grid tied system

                            Greetings,

                            The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

                            You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

                            Bright Blessings,
                            Kim


                            At 07:32 AM 10/27/2006, you wrote:

                            Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts –
                             
                            Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
                             
                            Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,… such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc…) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
                             
                            So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn’t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let’s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?    
                             
                            Gary Beck, P.E.
                            Eco-Holdings LLC
                            P.O. Box 25248
                            Houston , Texas 77265
                             
                            Tel: 713-530-1950
                            Fax: 832-201-5338

                             

                             

                          • Sean Kaylor
                            I noticed that the discussion began with dual wiring schemes. My father is a plans examiner in California and he has told me about the new electrical codes
                            Message 13 of 19 , Oct 30, 2006
                            • 0 Attachment

                              I noticed that the discussion began with dual wiring schemes. My father is a plans examiner in California and he has told me about the new electrical codes which address such issues. Apparently the DC system requires a plug arrangement that is not of the typical three prong setup so as to avoid confusion of mistakenly plugging DC equipment into AC equipment or vice versa. There are also several requirements regarding breaker capacity, segregation of systems and wire gauge, in short more work that few electricians know how to do.

                              From my own experience with stand alone dual voltage arrangements I can testify that it is a pain and potentially very dangerous. I would much rather be shocked by 120 volts at a fraction of the amperage than low voltage DC operating at very high amperage. With modern efficient grid-intertie inverters and the pains associated with two wiring schemes I would have to say that DC is just not practical from a grid intertie perspective.

                              Sean 


                              From: "Gary Beck" <eco@...>
                              Reply-To: hreg@yahoogroups.com
                              To: <hreg@yahoogroups.com>
                              Subject: RE: [hreg] Re: grid tied system
                              Date: Sun, 29 Oct 2006 19:08:26 -0600

                              Interesting - 100 watts when everything is �off�.  Times 100,000,000 households is 3000 Megawatts (or did I miss a zero?). If not, this is about 6 merchant power plants operating 24x7.

                               

                              If each house turned on just 3 � 60 Watt incandecent (hot) light bulbs, this jumps above 10,000 MW. So now 20 merchant plants each likely burning some type of fossil fuel and we have just 3 lights on.

                               

                              Actually, due to transmission and distribution losses, many more plants burning much more fuel. Solar-DC-Battery auxilary wiring for lighting alone sounds even better.

                               


                              From: hreg@yahoogroups. com [mailto:hreg@yahoogroups. com] On Behalf Of Prasad Enjeti
                              Sent: Sunday, October 29, 2006 5:44 PM
                              To: hreg@yahoogroups. com
                              Subject: Re: [hreg] Re: grid tied system

                               

                              Here is another link which details the amount of standby power all our home appliances consume. Click on the link on the left - Home Tours.. a typical US home consumes ~ 100 Watts of electricity when everything in the house is turned off..

                               

                              ************ ********* ********* ********* ********* ********* ***
                              Dr. Prasad Enjeti Power Electronics & Power Quality Laboratory
                              Professor, Fellow of IEEE Department of Electrical Engineering
                              Texas A&M University
                              College Station, TX - 77843-3128
                              Tel: 979-845-7466
                              Fax: 979-845-6259
                              Email: enjeti@.... edu ; http://enjeti. tamu.edu
                              ************ ********* ********* ********* ********* ********* ****

                               

                              ----- Original Message ----
                              From: Jim & Janet <jhd1@earthlink. net>
                              To: hreg@yahoogroups. com
                              Sent: Sunday, October 29, 2006 5:05:05 PM
                              Subject: Re: [hreg] Re: grid tied system

                              Here is a link to a voltage drop calculator. The easy way.

                              Or if you are a numbers kinda guy, try this.

                              But don't think that line losses only affect DC power. Here is something interesting if you are really concerned with your energy costs.

                              Jim Duncan

                               

                              ----- Original Message -----

                              From: Gary Beck

                              Sent: Sunday, October 29, 2006 12:31 PM

                              Subject: RE: [hreg] Re: grid tied system

                               

                              The DC line loss is an interesting aspect versus DC-AC-DC-AC electrical conversion losses and associated waste heat production.  Any idea how DC line loss compares over 10 feet or 50 feet for typical residential gauge copper wire? A few percent? 10%?

                              My point is that solar PV is inherently already a �local� or a distributed low voltage DC power system (rather than a remotely produced and transmitted high voltage power system*).  In comparison a DC-AC-DC-AC path provides multiple opportunities for both electrical energy loss and indoor waste heat production.  Anyone know how do the efficiency conversion numbers might compare?

                              (1) Solar PV-DC to 110 V AC (Electrically - how efficient? 90%, 75%?, Waste heat production is not a direct issue since transformer is outdoors, in garage or attic, etc.)

                              (2) 110V AC to V DC (computer power supply, battery charging etc.  (Same electrically efficiency? 90%, 75%? Plus unfortunately this one causes indoor waste-heat production)

                              (3) Added AC power* to remove this waste-heat from the house � motor driven electrical refrigeration �btu removal� has a pretty low efficiency - 50%

                              So even with a �does-it-stick- on-the-wall�  guess, when it happens in this way, I think you are looking at somewhere around 50% to 70% energy �loss� for such a DC-AC-DC-AC path Vs maybe 10% for direct DC path.

                              Forget about all �DC� appliances since this is not remotely practical. But consider if on a regional �sunny state� scale, what would happen only if 25% of all future residential lighting and 25% of all residential computer operation power were provided by direct solar DC 18-24V power battery sources?

                              Gary Beck, P.E.

                              Eco-Holdings LLC

                              * This arguement does not even consider that an AC high voltage power production distribution system such as a NG fueled merchant power plant with long transmissions lines is below 40% efficiency for converting NG fuel BTUs to electrical kWs before counting any transmission losses.


                              From: hreg@yahoogroups. com [mailto: hreg@yahoogroups. com ] On Behalf Of Garth & Kim Travis
                              Sent: Friday, October 27, 2006 7:52 AM
                              To: hreg@yahoogroups. com
                              Subject: RE: [hreg] Re: grid tied system

                              Greetings,

                              The original electric grid, way back was DC not AC, but then Tesla came up the the AC current and that is what we use.  Why?  DC has major line losses.  I do run some of my stuff directly off DC, but I am very careful to have my batteries really close to where I am using it.  Not a concept that is child friendly.  When wiring a home for AC, until you get a run over 40', you generally don't worry about putting in more copper to prevent line losses.  With DC power, the line losses can be measured on a 10' run.  So, unless the power supply is extremely close to where it will be used, the line losses will more than make up for any power savings.  This is especially true for any centralized power system in the home.

                              You have part of the equation very correct, we need to deal with all the heat that our modern living generates.  A home that is not designed to get rid of the heat build up will be very expensive to opperate.  Good ventilation is required.

                              Bright Blessings,
                              Kim


                              At 07:32 AM 10/27/2006, you wrote:

                              Some morning thoughts on solar, PVs, energy efficiency, and off grid concepts �
                               
                              Zero Energy Homes - There are low and zero power home designer/builders in Texas in business now. Their concepts are always based on an extreme low energy envelope and maximum natural lighting (an oxymoron of sorts). Then a large PV and solar hot water system is financed in the mortgage allowing an effective payout over 30 years (versus trying to justify the cost in your mind which thinks in much shorter time periods).
                               
                              Wasted heat counts - Every time you convert DC to AC, or low voltage to high voltage, or then convert (again) high voltage to low voltage,� such as for a desktop computer (happen internally), a laptop, or any other transformer driven device (answering machine, rechargeable tool, Xbox, cordless phone, florescent lighting, etc�) you waste and loose energy in the form of heat, which you then again waste energy again through its removal by running your air conditioning.
                               
                              So my big thought of the morning and question to HREG (and to anyone listening from G.E., Siemens, Sony, Panasonic, Samsung) why hasn�t someone come up with a home dual wiring scheme for purchase 110 Volt-AC and for produced let�s say 24 Volt-DC or 19.9 Volt-DC (a number I remember from my laptop converter). Or even simpler just sell a PV-Battery home install kit system to connect only to (a few) of your many home computer devices (HP-Compaq and Reliant - are you listening too?). How much energy would that alone save in Texas ?    
                               
                              Gary Beck, P.E.
                              Eco-Holdings LLC
                              P.O. Box 25248
                              Houston , Texas 77265
                               
                              Tel: 713-530-1950
                              Fax: 832-201-5338

                               

                               


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